#!/usr/bin/env node

//自定义可读流
const {Readable} = require('stream');
class MyReadable extends Readable{
  constructor(){
  super();
  }
  _read(){
    this.push(String.fromCharCode(this.#c++));
    if(this.#c > 'z'.charCodeAt(0)){
      this.push(null);
    }
  }
#c = 'a'.charCodeAt(0);
}

let rs = new MyReadable();
rs.pipe(process.stdout);
